Oracle compatibility: empty strings were not converted to NULL when using prepared statements.

h2/src/docsrc/html/changelog.html

@@ -20,7 +20,8 @@ Change Log
 <h1>Change Log</h1>
 
 <h2>Next Version (unreleased)</h2>
-<ul><li>PostgreSQL compatibility: new syntax "create index ... using ...".
+<ul><li>Oracle compatibility: empty strings were not converted to NULL when using prepared statements.
+</li><li>PostgreSQL compatibility: new syntax "create index ... using ...".
 </li><li>There was a bug in DataType.convertToValue when reading a ResultSet from a ResultSet.
 </li><li>Pull request #116: Improved concurrency in the trace system.
 </li><li>Issue 609: the spatial index did not support NULL.

h2/src/main/org/h2/expression/Parameter.java

@@ -14,6 +14,7 @@ import org.h2.table.TableFilter;
 import org.h2.value.Value;
 import org.h2.value.ValueBoolean;
 import org.h2.value.ValueNull;
+import org.h2.value.ValueString;
 
 /**
  * A parameter of a prepared statement.
@@ -83,6 +84,11 @@ public class Parameter extends Expression implements ParameterInterface {
 
     @Override
     public Expression optimize(Session session) {
+        if (session.getDatabase().getMode().treatEmptyStringsAsNull) {
+            if (value != null && value instanceof ValueString) {
+                value = ValueString.get(value.getString(), true);
+            }
+        }
         return this;
     }
 

h2/src/test/org/h2/test/db/TestCompatibilityOracle.java

@@ -6,6 +6,7 @@
 package org.h2.test.db;
 
 import java.sql.Connection;
+import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.sql.Statement;
@@ -90,6 +91,17 @@ public class TestCompatibilityOracle extends TestBase {
         assertResult(new Object[][] { { 1, new byte[] { 10 } }, { 2, null } },
                 stat, "SELECT * FROM E");
 
+        stat.execute("CREATE TABLE F (ID NUMBER, X VARCHAR2(1))");
+        stat.execute("INSERT INTO F VALUES (1, 'a')");
+        PreparedStatement prep = conn.prepareStatement(
+                "INSERT INTO F VALUES (2, ?)");
+        prep.setString(1, "");
+        prep.execute();
+        assertResult("2", stat, "SELECT COUNT(*) FROM F");
+        assertResult("1", stat, "SELECT COUNT(*) FROM F WHERE X IS NULL");
+        assertResult("0", stat, "SELECT COUNT(*) FROM F WHERE X = ''");
+        assertResult(new Object[][]{{1, "a"}, {2, null}}, stat, "SELECT * FROM F");
+
         conn.close();
     }